Abstract
The following current issues in verification and validation (V&V) are discussed: probability bounds analysis (PBA) versus the traditional probability distribution function (PDF) approach as used in the ANSI Standard document ASME V&V 20-2009; strict frequentist versus Bayesian approaches; model form uncertainty (and confusion) in prediction versus validation; Popper's philosophical falsificationism versus common sense; climate model trend validations versus climate change deniers; and V&V state of the art versus practice. Also, the many fundamental contributions to modern V&V practice in the history of the ASME Fluids Engineering Division and the Journal of Fluids Engineering (JFE) are described.